Mold and process of making the same



March 1927 w. M. SHEFFIELD MOLD AND PROCESS OF MAKING THE SAME Original Filed Nov. 2 1925 I Patented Mar. 15, 1927.

' copending application,

. tion by means of which a cavity of UNITED. STATES M. SHEFFIELD, OF NEW YORK, N. Y.

morn AND rnocnss or MAKING run SAME.

Application filed November 27,

The present invention is an improvementon the pulp mo ding machines and the like. Molds have usually been made with perforate walls of wire mesh or other fabric. Such mold walls are fragile, leave an imprint-of-their mesh on the molded surface and cannot well be used to produce sharply angled outlines.

In the copending application of Felix Louisot, Serial No. 35,848, filed on June 9, 1925, there is disclosed a mold formed of thin metal plates, laminae, alternate laminae being cut back or to form'drainage channels. In making this mold it is necessary to clamp the plates together and cut all the plates to the level of the desired outline. The laminae are then separated, the alternate laminae are cut back the desired distance, and the laminae again reassembled. This is a tedious and expensive process.

It is the object of the present invention to produce a mold of the type disclosed in said but in a more expeditious and convement manner. This aim is accomplished by forming the alternate laminae of paper or like material and cutting them back the desired distance by subjecting the assembled laminae to the action of an acid, or other decomposing medium.

In the drawing Fig. 1 is a-sectional view of the assembled mold.

Fig. 2 is an enlarged sectional'view of part of the laminae as originally assembled.

Fig. 3 is a view similar-Ito Fig. 2, showing the laminae after being treated with an acid. Fig. 4 is a cross-section on line 44 of Fig. 3.

Referring more particularly to the drawing, the mold is composed of two separable arts 1 and 2. The walls of each part are uilt up of alternating laminations of paper and reslstant metal, shown at 3 and 4 respectively. The thickness of the laminae is exaggerated for purposes of illustration, but obviously it may be varied as desired.

The laminae are assembled under pressure and are then permanently secured together.

5. The laminated block a cutting operathe desired configuration is formed therein, as shown in Fig. 2. 1

The block is next immersed in an acid bath for a length of time. The acid has no effect by rivets or bolts thus formed is subjected to erforate molds heretofore used in.

1925, Serial No. 71,659. Renewed July 24, 1928.

on the metal but attacks and disintegrates the exposed edges of the paper laminae. The acid cannot seep between the laminae due to the pressure used in their assembly.- After a certain period in the acid bath the block is removed and the disintegrated paper washed away from its lodginent between the metal laminae.

The acid treatment is repeated as often as is necessary to eat the paper laminae back the proper distance to form adequate drainage channels. The blockis then in the condition shown in Fig. 3, the drainage channels being indicated at 6 with the cavity-defining edges of 7the metal plates extending therebetween at 1 a The drainage channels are so minute that the pulp doesonot enter these channels but remains on the substantially smooth surface formed by the edges of the metal laminae, allowing the water to escape through the drainage channels.

By this process a mold is formed which can produce an article having any desired angular conformation and carrying no noticeable imprint of the mold. At the same time the process is simple and inexpensive.

While I have disclosed a mold tormed of alternate laminae of metal and paper, I could use any suitable materials, the essence of the process lying 1n formlng every other lamina of such a material that a portlon at the edge can be removed without disassembling the laminae. i

The mold can also be produced by using spacing laminae preformed to such a shape that they will, when assembled between the cavity-defining laminae, terminate outside the boundaries of the desired cavity. The spaces between the free ends of the cavity-defining laminae are then filled with melted paraflin, which upon hardening supports the cavitydefining laminae during the cutting operation. The block is then subjected to the cutting operation, after which the paraffin is removed from the block by melting. This method also produces a laminated mold having drainage channels without requiring the separation of the plates once they have been assembled.

What I claim is: 1. A mold composed of laminae and laminae of metal.

2. A mold composed of alternating laminae of paper and metal.

3. A mold of laminate structure having alternate laminations made of paper.

4. A mold of laminate structure having some of its laminae composed of acid resistant material and others of its lamina; composed of material decomposable b acid.

5. A mold of laminate structure aving some of its laminae composed'of resistant material and others of its laminae composed of decomposable material. 4

6. A mold of laminate structure having some of its laminae composed of hard material and others of its laminae composed-of soft material.

7. A mold of laminate structure having some of its laminae composed of relatively I insoluble material and-others of its-laminae composed of relatively soluble material.

8. A mold of laminate structure havin a. mold cavity defined by the edges of a ternate laminae, the intervening laminae being made of paper and having their edges inset to provide drainage channels.

9. A mold of laminate structure having a mold cavity defined bylthe edges of alternate laminae, the intervening laminae being formed of a soluble material and having their edgesinset to provide drainage channels.

10. The method of forming a laminatemold which comprises assemblin alternating laminae of paper and metal: securing sa1d laminae together to form a block, cutting a cavity in said block, subjecting said block to acid treatment, and washing out the debris resulting from said acid treatment.

11. The method of forming a laminated mold which comprises assembling laminle of resistant and non-resistant material, permanentl securing said lamina; together to form a lock, cutting a cavity in said block some of. which are relatively less resistant than others, permanently securing said laminae togetherto form a block, cuttin a cavity in said block, and removing the edge portions of said less resistant laminae.

14. The method of forming a laminated mold which comprises assembling alternate spacing laminaeand cavity-defining" laminae to form a; block, the spacing laminae being preformed to terminate outside the boundaries of the desired cavity in the block, providing a means for supporting the cavitydefining laminae during cutting, cutting a cavity in said block, and removing the supporting means. Q

In testimony whereof I afiix my signature. WILLIAM M..SI-I EFFIELD.

a laminated 

